Features of atherosclerosis in patients with angina and no obstructive coronary artery disease

Background: An association between atherosclerosis and coronary vasospasm has previously been suggested. However to date, no conclusive data on the whole spectrum of these disorders have been published. Aims: This study aimed to define specific morphological features of atherosclerosis in patients with angina and no obstructive coronary artery disease (ANOCA) due to coronary vasospasm. Methods: From February 2019 to January 2020, we enrolled 75 patients referred to our laboratory for a coronary function test (CFT) due to ANOCA and suspected coronary vasomotor dysfunction. The CFT consisted of an acetylcholine test and a physiology assessment with hyperaemic indexes using adenosine. Patients were divided into two groups according to the presence or absence of coronary vasospasm triggered by acetylcholine (ACH+ and ACH-, respectively). In addition, optical coherence tomography (OCT) was performed to assess the lipid index (LI), a surrogate for lipid area, and the prevalence of markers of plaque vulnerability. Results: ACH+ patients had a higher LI than ACH- patients (LI: 819.85 [460.95-2489.03] vs 269.95 [243.50-878.05], respectively, p=0.03), and a higher prevalence of vulnerable plaques (66% vs 38%, p=0.04). Moreover, ACH+ patients showed a higher prevalence of neovascularisation compared to ACH- subjects (37% vs 6%, p=0.02) and a trend towards a higher prevalence of all individual markers, in particular thin-cap fibroatheroma (20% vs 0%, - 0.06). No differences were detected between patterns of coronary vasospasm. Conclusions: The presence of coronary vasospasm, regardless of its phenotype, is associated with higher lipid burden, plaque vulnerability and neovascularisation.